Conventionally, surface-mount electronic components are mounted onto circuit boards by the following methods. For example, an electronic component placed on a flexible circuit board is clamped, together with the circuit board, by a clamping member made of a metal plate from the underside of the circuit board, as disclosed in Japanese Patent Application Publication No. Hei 11-40917. According to a method disclosed in Japanese Patent Application Publication No. Hei 7-7249, the upper side of an electronic component placed on a flexible circuit board is covered with a film, and the peripheral portion of the film is secured to the circuit board by ultrasonic welding or the like.
Among electronic components are those having terminals projecting from their casing surfaces, such as sensor switches. Conventionally, such an electronic component is mounted onto a circuit board as follows. For example, an auxiliary board and a mounting member are placed over the electronic component positioned on the circuit board, and resilient portions provided on the mounting member are allowed to resiliently urge the terminals of the electronic component downwardly through the auxiliary board so that the terminals are pressed against electrode patterns on the circuit board, as disclosed in Japanese Patent Application Publication No. 2002-164674.
The above-described conventional electronic component mounting structures suffer, however, from the following problems. Because electronic components have to be mounted onto a circuit board one by one, if a large number of electronic components need to be mounted onto the circuit board, each electronic component may fail to be mounted in the desired position, resulting in an unreliable connection between the circuit board and the electronic components. In addition, mounting of electronic components cannot be efficiently carried out.